Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/20—Controlling the colour of the light
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
  • H05B47/10—Controlling the light source
  • H05B47/175—Controlling the light source by remote control

Definitions

• the present invention relates to the field of lighting devices, and more particularly to a LED lighting system with a distribution of LED controllers.
• Luminaires based on red, green, and blue (RGB) light-emitting diodes generate various colors of light, which produce white or colored light when properly combined.
• RGB LED luminaires are used, for example, in LCD back-lighting, commercial- freezer lighting, and white light illumination.
• the controller of the light engine receives from a user or a higher level system, e.g. a building management system, the desired or targeted color point and light level.
• These setting values can be specified with tristimulus values in CIE x, y, L representing a certain position in the CIE 1931 chromaticity diagram created by the Commission Internationale de l'Eclairage (CIE), and thus need to be transformed into duty cycles or power levels for each connected LED color. Then, the transformation can be individually performed by a distribution of LED controllers through a calibration matrix (inverted C-matrix) shared between all of them.
• CIE Commission Internationale de l'Eclairage
• LED-based luminaires presents difficulties because the optical and electrical properties of individual LEDs vary with temperature, forward current, aging and manufacturing process.
• change in temperature of the LED p-n junction leads to changes in light flux output and peak wavelength of the LED, such that the calculations through the calibration matrix are also temperature dependent.
• each LED controller can perform the aforementioned calculations independently of the other since a single row of the calibration matrix is needed.
• the LED controllers are required to communicate between them through the parameters of the calibration matrix to achieve a logical behavior. But this is not always possible according to the architecture of the light engine.
• a lighting system as claimed in claim 1 a method of adjusting internally a out-of-gamut targeted value as claimed in claim 18, a method of adjusting internally a out-of-range targeted value as claimed in claim 20, a method of adjusting externally, e.g. through an external user or a higher level system, a out-of-gamut and/or out-of-range targeted value as claimed in claim 22, and a method of adjusting internally and externally a out-of-gamut and/or out-of-range targeted value as claimed in claim 24, and a computer program as claimed in claim 25.
• a lighting system comprising: at least one light emitting diode (LED); a communication databus; a controller for controlling the communication databus in broadcast mode; a plurality of control units for individually controlling each of the at least one LED, each control unit being in data communication with the controller via the databus; wherein, the controller is input by at least one targeted value from a user and broadcasts, via the databus, the at least one targeted value towards the plurality of control units; at least one amongst the plurality of control units has an incapacity to comply with the at least one targeted value, and each of the at least one amongst the plurality of control units transmits a signal for notifying upon the incapacity; the controller broadcasts, via the databus, an adjusted value with respect to the at least one targeted value towards the plurality of control units.
• the solution as an adjusted value can be communicated to all the control units thanks to the databus in broadcast mode, such that the lighting system can ensure a logical behavior when handling target values it
• the adjusted value may be a value adjusted by the controller in response to the signal transmitted by each of the at least one amongst the plurality of control units towards the controller. Thereby, the controller is notified upon the incapacity of at least one control unit to comply with the at least one targeted value.
• the adjusted value may be a value desaturated with respect to the at least one targeted value, and in particular a desaturated color point, such that the at least one targeted value may be considered by the lighting system as a out-of-gamut color point.
• the adjusted value may be a value selected by the controller amongst the values adjusted by each of the at least one amongst the plurality of control units, the signal being transmitted towards the controller and further comprising the values adjusted by each of the at least one amongst the plurality of control units.
• the controller is notified upon the incapacity of at least one control unit to comply with the at least one targeted value, and also upon the solutions as adjusted values proposed by each of the at least one control unit to comply with the at least one targeted value.
• a single adjusted value is selected, and the desaturated value is prioritized over the selected value.
• Each of the values adjusted by each of the at least one amongst the plurality of control units may be a value reduced with respect to the at least one targeted value. Thereby, the selected adjusted value will be a value reduced with respect to the at least one targeted value.
• the adjusted value selected by the controller may be the lowest value amongst the values adjusted by each of the at least one amongst the plurality of control units. Thereby, all the control units will comply with the adjusted value broadcast to all of them by the controller over the databus.
• the adjusted value may be a reduced light level at the color point with respect to the at least one targeted value, such that the at least one targeted value may be considered by the lighting system as a out-of-range light level at the color point.
• the adjusted value broadcast by the controller may be originated from the user.
• the value may be adjusted by the user in response to the signal transmitted by each of the at least one amongst the plurality of control units towards the user.
• the at least one targeted value may be externally adjusted, in response to the notification upon the incapacity of at least one control unit to comply with the at least one targeted value, received by the user.
• the value may already be adjusted. For example, it may be the value selected by the controller, the value directly adjusted by the controller, the value adjusted by the control unit if alone to be not in compliance with the at least one targeted value, or a combination between them.
• the user is thus not only notified upon the incapacity of at least one control unit to comply with the at least one targeted value, but also notified upon the solution.
• the signal transmitted by the at least one control unit unable to comply with the at least one targeted value towards the controller may be carried out via the bus, namely internally.
• the signal transmitted by the at least one control unit unable to comply with the at least one targeted value towards the user is carried out via a feedback link, namely externally.
• the at least one targeted value may be transformed through a calibration matrix into a duty cycle for each color emitted by the at least LED.
• the calibration matrix is shared by all of the control units, such that a communication between them is required in the case that the targeted value cannot be rendered by the lighting system.
• a method of adjusting internally a out-of-gamut targeted value a method of adjusting internally a out-of-range targeted value, a method of adjusting externally, e.g. through an external user or a higher level system, a out-of-gamut and/or out- of-range targeted value, and a method of adjusting internally and externally a out-of-gamut and/or out-of-range targeted value.
• the steps of the previous methods can be carried out by a computer program including program code means, when the computer program is carried out on a computer.
• Fig. 1 shows a block diagram of a LED lighting system 100 according to an exemplary embodiment of the present invention, in the case that the LED controller 3OR is unable to comply with the targeted setting values;
• Fig. 2 shows a schematic flow diagram of a transmission link according to a first and fourth exemplary embodiment of the present invention, in the case that the LED controller 3OR of Fig. 1 is unable to comply with the targeted setting values
• Fig. 3 shows a schematic flow diagram of a transmission link according to a second and third exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values;
• Fig. 4 shows a schematic flow diagram of a transmission link according to a fifth exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values.
• Fig. 1 is a block diagram of a LED lighting system 100 according to an exemplary embodiment of the present invention, in the case that the LED controller 30R is unable to comply with the targeted setting values.
• the LED lighting system 100 can produce white light or colored light by mixing in an appropriate way the output of the different LEDs 1OR, 1OG, 1OB, and it can be used for illumination or lighting purposes.
• the LED lighting system 100 e.g. a light engine, is a multi-core architecture comprising a light bar of at least one light emitting diode (LED) 1OR, 1OG, 1OB, typically three LEDs of different primary colors: red R, green G and blue B.
• LED 1OR, 1OG, 1OB is connected to a respective driver 2OR, 2OG, 2OB for allowing current to flow through each of them.
• the drivers 2OR, 2OG, 2OB are individually controlled by a distribution of respective LED controllers 30R, 30G, 30B, i.e. control units.
• the LED lighting system 100 further comprises a central controller 40 and a communication databus 50.
• the targeted setting values e.g.
• a color point and/or a light level are externally input by a user 60 or a higher level system, e.g. a building management system, to the central controller 40, which then broadcasts the targeted setting values over the databus 50 to all the LED controllers 30R, 30G, 30B.
• the targeted setting values are specified with tristimulus values in CIE x, y, L representing a certain position in the CIE 1931 chromaticity diagram.
• the LED controllers 3OR, 3OG, 3OB individually carry out some calculations for allowing the targeted setting values to be transformed, through a shared calibration matrix (inverted C-matrix), into a duty cycle or power level for each LED color R, G, B.
• Fig. 2 depicts a schematic flow diagram of a transmission link according to a first exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values.
• the broadcast targeted setting values are invalid or out-of-gamut color points and/or out-of-range light levels at a color point
• each of the LED controllers 30R, 30G, 30B that is unable to comply with these values, e.g. the LED controller 30R as illustrated in Figs 1 and 2, sends a feedback signal over a link 70 back to the external user 60 or a higher level system, in order to inform them about this abnormal situation (arrow 1).
• the user 60 or the higher level system can decide on new targeted setting values, i.e. adjusted values, submitted to the central controller 40 (arrow 2), which then broadcasts them over the databus 50 to all the LED controllers 30R, 30G, 30B (arrow 3).
• the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• the adjusted values may be either reduced values if the broadcast targeted setting values are out-of-range light levels or desaturated values if the broadcast targeted setting values are out-of-gamut color points.
• Fig. 3 depicts a schematic flow diagram of a transmission link according to a second exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values.
• the broadcast targeted setting values are out-of-gamut color points
• each of the LED controllers 30R, 30G, 30B that is unable to comply with these values e.g. the LED controller 30R as illustrated in Figs 1 and 3
• the central controller 40 can then decide to desaturate the color while rendering the color closest to the targeted color point.
• the new targeted setting values i.e.
• Fig. 3 also depicts a schematic flow diagram of a transmission link according to a third exemplary embodiment of the present invention, in the case that the LED controller 3OR of Fig. 1 is unable to comply with the targeted setting values.
• the broadcast targeted setting values are out-of-range light levels at a color point
• each of the LED controllers 3OR, 3OG, 3OB that is unable to comply with these values, e.g.
• the LED controller 30R as illustrated in Figs 1 and 3, sends a signal over the databus 50 from each of the LED controllers 30R, 30G, 30B that are unable to comply with these values, e.g. the LED controller 30R as illustrated in Figs 1 and 3, back to the internal central controller 40, in order to notify it upon this abnormal situation and also to propose it a new targeted light level at the color point that each can support, i.e. a reduced light level (arrow 1).
• the central controller 40 then broadcasts over the databus 50 the new targeted setting values, i.e. the newly adjusted light level at the color point, to all the LED controllers 30R, 30G, 30B (arrow 2).
• the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• the central controller 40 in response to the signals sent by each of these LED controllers 30R, 30G, 30Bs, selects the lowest light level at the color point amongst the light levels sent by these signals, and broadcasts over the databus 50 the color point with the newly adjusted light level to all the LED controllers 30R, 30G, 30B. Again, the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• the targeted color point is prioritized over the targeted light level, and this matches with the eye sensitivity to color point differences higher than the eye sensitivity to the light level differences. It is furthermore to be noted that every entity in the LED lighting system 100 still deals with the color point information of a single color.
• Fig. 2 also depicts a schematic flow diagram of a transmission link according to a fourth exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values and the broadcast targeted setting values are out-of-range light levels at a color point.
• the LED controller 30R sends a feedback signal over the link 70, as illustrated in Figs 1 and 2, back to the external user 60 or a higher level system, in order to notify them upon this abnormal situation and also to propose them a reduced light level as a solution (arrow 1).
• the user 60 or the higher level system can then decide either to submit these new targeted setting values to the central controller 40 (arrow T), which then broadcasts them over the databus 50 to all the LED controllers 3OR, 30G, 30B (arrow 3), or to submit other values (arrow T).
• the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• the central controller 40 communicates after selection the solution, i.e. the lowest light level at the color point amongst the light levels sent by each of these LED controllers 30R, 30G, 30B, towards the external user 60 or the higher level system.
• the user 60 or the higher level system can then decide either to submit these new targeted setting values back to the central controller 40, which then broadcasts them over the databus 50 to all the LED controllers 30R, 30G, 30B, or to submit other values.
• the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• Fig. 4 depicts a schematic flow diagram of a transmission link according to a fifth exemplary embodiment of the present invention, in the case that the LED controller 30R of Fig. 1 is unable to comply with the targeted setting values and the broadcast targeted setting values are out-of-gamut color points.
• the LED controller 30R sends a signal over the databus 50, as illustrated in Figs 1 and 4, back to the internal central controller 40, in order to notify it upon this abnormal situation (arrow 1).
• the central controller 40 can then decide to desaturate the color while rendering the color closest to the targeted color point.
• the central controller 40 communicates, as solution, the new targeted setting values, i.e.
• the newly adjusted color point with the targeted light level towards the external user 60 or the higher level system (arrow T).
• the user 60 or the higher level system can then decide either to submit these new targeted setting values back to the central controller 40 (arrow 3), which then broadcasts them over the databus 50 to all the LED controllers 30R, 30G, 30B (arrow 4), or to submit other values (arrow 3).
• the process repeats until the targeted setting values can be rendered by the LED lighting system 100.
• the central controller 40 can be considered as a "dumb” controller, which just controls the databus 50 in broadcast mode, and the fact that no entity (central controller 40, databus 50, LED controllers 30R, 30G, 30B, etc.) inside the LED lighting system 100 has a gamut knowledge, the present invention shows that it is possible of handling the targeted setting values wherein the color point and/or light level is invalid or out-of-range.
• a LED lighting system 100 comprising at least a central controller 40 for just controlling a communication databus 50 in broadcast mode, and a distribution of LED controllers 30R, 30G, 30B for individually controlling each LED 1OR, 1OG, 1OB through a respective driver 2OR, 2OG, 2OB, has been described.
• the central controller 40 broadcasts targeted setting values from an external user 60 to all the distributed LED controllers 30R, 30G, 30B through the databus 50.
• the LED controllers 30R, 30G, 30B convert the values using a shared calibration matrix into transformed values for each LED color R, G, B.
• the targeted setting values can be properly adjusted either externally through a feedback signal sent over a link 70 back to the user 60, or internally through a notification signal broadcast over the databus 50 back to the central controller 40.
• a computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

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• Circuit Arrangement For Electric Light Sources In General (AREA)

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• 2009
  • 2009-02-02 EP EP09707402A patent/EP2243334A2/de not_active Ceased
  • 2009-02-02 US US12/866,445 patent/US8368319B2/en not_active Expired - Fee Related
  • 2009-02-02 CN CN2009801044428A patent/CN101940064B/zh not_active Expired - Fee Related
  • 2009-02-02 WO PCT/IB2009/050415 patent/WO2009098633A2/en not_active Ceased

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